DESCRIPTION: The overall objective of this study is to evaluate the immune system in the male reproductive tract as it relates to HIV infection. The PI proposes to determine the relationship between clinical parameters such as HIV-1 disease stage, antiviral therapy, genital tract inflammation and viral load, and measures of HIV-1 specific immunity in semen including antibody profiles, T cell phenotypic and functional characteristics, and immunoregulatory cytokine profiles. Further, they will perform a prospective study in newly seroconverted male patients of viral load and the development of cellular and humoral mucosal immune responses with the goal of demonstrating that these parameters differ from that in peripheral blood. Finally, they will evaluate CTL activity in semen from long-term non progressors and compare specificity of this activity to that in the peripheral blood. The study will employ archived semen from CDC and other sources, as well as prospectively collected specimens from the Fenway HIV Clinic. The purpose of these studies are to (i) determine if male genital tract CTLs represent a restricted or specialized cell population, and to (ii) provide information concerning CTL epitopes that may control HIV-1 infection in the genital tract.